From 041ee6f3727a5efdc497d0363ab5ffbd98a2c77c Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 2 Jun 2025 21:21:55 +0200 Subject: [PATCH] kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management Unbound kthreads want to run neither on nohz_full CPUs nor on domain isolated CPUs. And since nohz_full implies domain isolation, checking the latter is enough to verify both. Therefore exclude kthreads from domain isolation. Signed-off-by: Frederic Weisbecker Reviewed-by: Waiman Long Cc: Marco Crivellari Cc: Michal Hocko Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Cc: Vlastimil Babka Cc: Waiman Long --- kernel/kthread.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 85ccf5bb17c9e..968fa5868d216 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -362,18 +362,20 @@ static void kthread_fetch_affinity(struct kthread *kthread, struct cpumask *cpum { const struct cpumask *pref; + guard(rcu)(); + if (kthread->preferred_affinity) { pref = kthread->preferred_affinity; } else { if (kthread->node == NUMA_NO_NODE) - pref = housekeeping_cpumask(HK_TYPE_KTHREAD); + pref = housekeeping_cpumask(HK_TYPE_DOMAIN); else pref = cpumask_of_node(kthread->node); } - cpumask_and(cpumask, pref, housekeeping_cpumask(HK_TYPE_KTHREAD)); + cpumask_and(cpumask, pref, housekeeping_cpumask(HK_TYPE_DOMAIN)); if (cpumask_empty(cpumask)) - cpumask_copy(cpumask, housekeeping_cpumask(HK_TYPE_KTHREAD)); + cpumask_copy(cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN)); } static void kthread_affine_node(void) -- 2.47.3